What this article looks is to think the philosophical existential problem that turned, after Nietzsche’s philosophy, the God's topic since I Base at the beginning of the 20th century in the light of two big thinkers: Heidegger and Zubiri. By means of the crisis of Zubiri’s faith we can feel what was happening to him to the whole epoch at the beginning of century and how another philosophy was necessary, that of Heidegger, to be able to rethink and live through the experience of the Foundation.